WASHINGTON (CNN) --The U.S. and UK governments have defended their decision to oust Saddam Hussein despite an assertion by the leader of a team of experts that Iraq probably never had weapons of mass destruction.

White House officials and British ministers on Monday both said the removal of the Iraqi dictator justified the war regardless of whether he ever had banned weapons.

The Bush administration said it intended to eventually review pre-war intelligence on Iraq's weapons of mass destruction.

But White House spokesman Scott McClellan said the Iraq Survey Group, a team of experts looking for WMD, should continue the search despite comments from its former leader, David Kay, that no stockpiles probably exists.

"We need to compare the intelligence before the war with what the Iraq Survey Group learns on the ground," said McClellan. "Their mission is ongoing and their work is ongoing."

British Foreign Secretary Jack Straw, in a BBC radio interview Monday, said it was "disappointing" that no nuclear, biological or chemical weapons had been found, but the world was better off without Saddam.

"Our judgment was, and my judgment remains, that Saddam did indeed pose a threat to Britain's security, as to the European Union's and the rest of the world," he added.

"And if we look at what has happened in the last year I will repeat the point that we have removed a terrible tyrant."

Kay, who stepped down as the CIA special adviser leading the Iraq Survey Group last week, will be replaced by Charles Duelfer, a longtime weapons inspector. (Full story)

In a series of radio and newspaper interviews over the weekend, Kay poured buckets of water on theories that Saddam Hussein was ready to use WMD on his enemies.

"My summary view, based on what I've seen, is we're very unlikely to find large stockpiles of weapons," he told NPR's Weekend Edition. "I don't think they exist." (Full story)

Kay blamed the intelligence agencies, telling NPR he thinks "the intelligence community owes the president (an explanation) rather than the president owing the American people."

McClellan, traveling with President George W. Bush in Arkansas, was asked repeatedly by reporters if the White House still believes weapons of mass destruction will be found -- but he did not reply. In the past, he has insisted WMD would be found.

But he continued to defend the U.S. decision to go to war in Iraq as the "right decision.

"Saddam Hussein was a dangerous threat. The world is safer because of the actions we took," said McClellan.

"What we know today only reconfirms that the president made the right decision," said McClellan, insisting that Kay's interim report in the fall confirmed "that Saddam Hussein was in material breach of" of United Nations Resolution 1441.

Both Bush and his main ally UK Prime Minister Tony Blair have come under pressure over the absence of WMDs in Iraq.

U.S. Senate Minority Leader Tom Daschle on Monday called for an independent look into "the intelligence failures leading up to war with Iraq," saying it was the Senate's obligation to do so.

Straw: Saddam was a threat

"I cannot overstate the significance of these claims (by Kay)," the South Dakotan said on the Senate floor. "They led directly to the decision to go to war last spring.

"Obviously that wasn't the only motivation, but it was a decision that was based on erroneous information," he said. "We have made the fateful decision, and now 500 Americans have been killed."

And in Britain, Blair and several key officials face criticism this week when Lord Hutton publishes his report into the death of weapons expert David Kelly last July.

The scientist was found dead near his home in southern England days after being exposed as the source of a BBC report claiming the prime minister's office exaggerated the threat posed by Saddam to justify war. (Analysis)